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Discussion Starter #1
Has anyone here encountered any trouble using these epoxy primers with air dry top coats? I used a High build primer and didn't allow enough cure time between primer and top coat. The PPG tech sheet specs were followed to a "T", but now I have to stip off the topcoat, sand and repaint. The store and PPG regional rep. basically blamed technique and temperature as the culprit. The paint has been dry for a month but it's not even close to being cured because the epoxy is still giving off fumes. Xylene wipes it off in seconds. I even tried running parts through a bake oven, but the topcoat lost its adhesion. Does anyone wonder if these reps just come around and make excuses to wear you out so you'll just shut up & put up? Live and learn I guess.
 

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as long as i know theres no bad reps its always people, guy behind spray gun that makes mistakes, i guess ur gun setup was wrong, since u say it still gives off fumes u probably shot it so wet, and didnt let time to flash off as ure SUPPOSED to or it will run and delaminate and just fail... have to read those p pages real good.
 

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I just painted my frame a couple weeks ago, epoxy primer waited 2 hrs. at 60 deg. then topped it with some acrylic enamel, no problems. How long did you wait to topcoat it ?

Later, Mark
 

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Discussion Starter #4
Hey its very likley its my fault after all. I'm a metal fabricator, not a painter. I've done a fair bit of painting, with good and bad equip. (I've never had formal training however.) I dont have a lot of experience with epoxies, mainly air dry xylene based industrial paints. It just frustrates me to no end that I followed the instructions VERY carefully. The spray pattern (on our new offshore devibiss copy POS) may have been the main underlying problem. We've used copys with good luck in the past, But none of us like the latest replacement gun we're currently using. Won't fan out well. (maybe I haven't gotten used to it yet) Still trying to figure it out.
 

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Discussion Starter #5
Hey hotRod... first session was about 1 hr (min rated topcoat time) Shop temp was 65deg. Since it didn't work well, I increased the shop temp to 70 deg. and waited 8 hrs to topcoat. It actually turned out worse. Thats the puzzling part. I have since priced some high end spray guns. Don't epoxy primers cure chemically? or do they flash off the same as other paints?
 

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Discussion Starter #7
The tip I was using was a 1.6 . The tech sheet spec'ed a 1hr to 24 window for topcoating. The primer and topcoat were both PPG products and compatable. I was however getting some heavy orange peel in some areas.(primer) I mixed with a power mixer and used no reducer. (Reducing was optional-was supposed to be ready to spray) I was told surface temp and shop temps are two different things, and a heavier coat would lengthen the recoat window significantly.(of course this was after the fact.) The shop owner offered to supply more top coat, which is decent I suppose.
 

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DP IS A OLD PRODUCT WHEN THEY CAME OUT WITH DPLF IT WAS NOT AS GOOD A SEALER.PUT DP AND ACTIVATER TOGETHER IT WILL NOT HARDEN FOR A LONG TIME.FOR THIS REASON WE SWITCHED TO PPG URETHANE SEALER IT COMES IN 3 COLORS DRIES FASTER AND DOSN'T SHRINK LIKE DP.I THINK DP HAS ITS PLACE BUT NEWER AND BETTER PRODUCTS HAVE MADE ITS USES LIMITED.WHEN DP CAME OUT IN 1980 OR SO IT WAS A GOD SEND FOR BARE METAL AND SEALING. ASK THE PPG REP ABOUT NEW SEALERS.
 

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I just wanted to add that I have limited experience on catalized epoxy primer/sealers. I have found that it is more than one or two very light coats WITH reducer, it takes up to a week to cure. I use quiet a bit with my s-10 and had no problems. I always shot the epoxy at the end of the weekend(weekend project) and let it dry for the week. I tryed working the day after, and there were always soft spots. They did cure over time though and gave a very hard, nice finish.

I am thinking that your temp was probably too low and the coat was too thick. It just needed more time to cure.

Chris
 

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Sounds like technique problem. Don't feel bad, I just did a spray job last week using $$polye$ter $ primer $$$ and forgot to put in the hardner! Expensive mistake not to mention the total mess of strippign off that semi-dry sticky gunk!!
 

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Discussion Starter #13
Thanks for the tips guys; I'm in the middle of removing the top coat, and I'll give it another try in a week or so. Stripping small parts is no problem, a dip in xylene for 2 mins and a brush off/ wipe down and its gone. Hasn't affected the primer at all...its rock hard. Thanks again.
 
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